Please note: While some information will still be current in a year, other information may already be out of date in three months time. If you are in any doubt, please feel free to ask.

G542X /5t and PA

My 7 year old son was diagnosed with carrying g542x and 5t.
This diagnoses was made when he was 6 years old after experiencing syringeal akrokeratoderma in his hands (exesive wrinkling of the palms) He has a sweat test of 39 and then 40
The wrinkling of the hands only lasted for about 3 months. My son also has inserted ear tubes at the age of 2 and 4 due to fluid build up.

We were told that our son would experience sinus infection and the possibility of the absence of his vas deference and not too worry. However the cf clinic wanted to observe him every 6 months. Recently my son had a wet cough which lasted for 5 weeks. He was seen by his pediatrician and confirmed that everything was ok, just had a regular cold.

During our recent cf check up, my son was diagnosed with pneumonia for the 1st time and was given amoxicillin (80) for ten days and the cough has dissapearded. However during the cf check up they performed a throat swab culture and the results came out positive for PA. ( it was negative 6 months ago)
The dr was surprised as he said that PA only appears in classic cf patients and asked us to repeat the test this week as well as a complete genetic panelling for the other 1500 cf mutations.

I did not know anything about PA until I came across this wonderful educational web site and I thank you for that. However it has gotten me extremely worried and started to disinfect my home with chloride.

Is it possible that we will find another cf gene? I will be getting the results in 2 months.
Also I have read that if PA is cought early it can be treated with a success rate of 80 percent. What is the definition of early? My son has level 1. What is the best treatment to eradicate PA? And what can I do to ensure that he does not get again?

From the bottom of my heart I thank you for taking the time to answer my questions.
Worried mom Mary.
Dear Mary
Thanks for sharing your concerns with us. You have several questions which we will try to answer separately.

Firstly, you would like to know if it is possible to find another gene. Usually when performing the initial search only a limited number of mutations in the CFTR gene are searched for. These are the most common mutations and are usually specific to your country or region. In most cases this identifies two mutations (one from the father and one from the mother). As you rightly say in your question, there are many mutations that can cause CF. It is possible that the extended screening for other mutations will detect another CF gene which is less common.

You also ask about the definition of “early”. When speaking about infection with pseudomonas aeruginosa there are many definitions of what is a “new” or “first” isolation of P. aeruginosa. They all agree that it is a positive result in a person who’s tests have previously been negative. When we consider “early” we now have to think about how often testing has been carried out (i.e. every 3 months is more likely to detect P. aeruginosa early versus every 6 months) and the method of obtaining the sample (i.e. sputum spontaneously produced is more likely to detect P. aeruginosa early than throat swabs). You may wish to discuss these practicalities further with your son’s CF team.

With regards to the best treatment to eradicate P. aeruginosa, this is still an active area of research. There are many trials published that compare different treatments for eradication. Mostly they combine an inhaled antibiotic (for example nebulised tobramycin or colistin) with an oral antibiotic (e.g. ciprofloxacin). Some trials have also explored intravenous antibiotics. The trials have suggested that eradication success rates of between 60 and 80% can be achieved. In other words, out of all patients treated, between 60 and 80% will be negative for P. aeruginosa by the end of treatment.

As you also correctly allude to in your question, P. aeruginosa can return at a later stage even if eradicated. You ask about strategies to prevent this from happening. It sounds like you are already very knowledgeable and are doing a great job with keeping your son’s home disinfected. The main reservoirs for P. aeruginosa in the home are sink drains, toilets and showers. It is a good idea to keep these clean and use a disinfectant. Other sources to be aware of are seawater near sewage outlets and polluted river outlets, ineffectively chlorinated swimming pools and jacuzzis/hot tubs and air humidifiers. It is recommended that individuals with CF do not come into contact with each other to avoid transmission of pathogens from person to person. It is also important to have a good hygiene routine with equipment like nebulisers or airway clearance equipment such as PEP masks. These should be washed with warm soapy water and allowed to thoroughly dry.

I hope our answer is of some help to you and your son. Please post another question if you would like any further information.
The answer is edited by: PhD Lisa Kent